The goal of the Molecular Biology Core is to maintain different yeast artificial chromosome (YAC) libraries and to provide the reagents which will be used by all projects. The program will acquire the 400 kb CEPH YAC library from Dr. David Housman's laboratory at MIT. The program is expected to receive the newly constructed large insert YAC libraries from CEPH. Most importantly, we will receive a chromosome 12 specific sublibrary that will be generated by CEPH. This library which is the key reagent for the proposed program will be the initial focus of attention for the Molecular Biology Core. DNA from each member of this approximately 1,000 member library will be prepared and some of it will be arrayed on nylon membranes. The purified DNA will be provided to Project 1 and the membranes will be provided to Projects 2 and 3. A second objective of this core is to oversee the preparation of oligonucleotide primers which will define sequence tagged sites for the physical mapping effort. Nearly 500 pairs of oligonucleotides need to be synthesized per year and the core will evaluate their quality. Finally, the core will be responsible for maintaining the different reagents that the project is receiving and generating. The core will also evaluate the most appropriate strategies for timely distribution of the mapping reagents which the program project will generate and the genes that it will identify.